Croton section Geiseleria (Gray, 1856) Baillon, 1858

Sodré, Rodolfo Carneiro & Silva, Marcos José Da, 2017, An overlooked new species of Croton section Geiseleria (Euphorbiaceae) from the Brazilian Cerrado, with a key to the species of this section occurring in the state of Goiás and in the Distrito Federal, Phytotaxa 329 (2), pp. 127-138 : 133

Key to the species of Croton section Geiseleria occuring in the state of Goiás and the Distrito Federal

1. Leaf margin entire or subentire ........................................................................................................................................................ 2

- Leaf margin serrate to crenate .......................................................................................................................................................... 4

2. Petioles 0.1–0.7 cm long, with disciform apical glands; leaf blades linear, 0.2–0.7 cm long, apex acute ( Fig. 4L, M ) ..................... ........................................................................................................................................................... C. junceus Baillon (1864: 339)

- Petioles 2.6–7.1 cm long, with obconical apical glands, leaf blades ovate or ovate-lanceolate, 4.8–8 cm long, apex acuminate or caudate .............................................................................................................................................................................................. 3

3. Pistillate sepals acuminate at the apex; anthers at least twice longer than wide ... C. leptobotryus Müller Argoviensis (1873: 155)

- Pistillate sepals acute at the apex; anthers as long as wide ( Fig. 5D, E ) ................................. C. pulegiodorus Baillon (1864: 361)

4. Leaf margins with stipitate-capitate glands in the sinuses ................................................................................................................ 5

- Leaf margins with or without sessile glands .................................................................................................................................... 7

5. Stipules with glands; leaf blades with acute apex; pedicels of pistillate flowers 5–9 mm long ( Fig. 4D–F ) ..................................... ................................................................................... C. gracilirameus M. J. Silva, Sodré & P. E. Berry in Silva et al. (2015: 162)

- Stipules without glands, leaf blades with acuminate, aristate or caudate apex; pedicels of pistillate flowers 1–4 mm long .......... 6

6. Leaves slightly bullate on the adaxial surface; pistillate sepals without glands .. C. mucronifolius Müller Argoviensis (1873: 216)

- Leaves plane and smooth on the adaxial surface; pistillate sepals with stipitate glands ( Fig. 6C–E ) ................................................. ......................................................................................................................................................... C. agoensis Baillon (1864: 348)

7. Petioles with oblong apical glands; pedicels of pistillate flowers 3.5–6.7 mm long ( Fig. 6K, L ) ...................................................... ................................................................................................................................... C. goyazensis Müller Argoviensis (1865: 120)

- Petioles with patelliform, cupuliform, cylindric-clavate or disciform apical glands; pedicels of pistillate flowers 0.1–2 mm long .. ........................................................................................................................................................................................................... 8

8. Pistillate flowers with 6–8 sepals ..................................................................................................................................................... 9

- Pistillate flowers with 5 sepals ....................................................................................................................................................... 11

9. Petiolar glands disciform stipitate, rarely subsessile; inflorescences with a distinct sterile zone between pistillate and staminate flowers; styles usually 2-fid ( Fig. 4N, O ) ............................ C. lundianus ( Didrichsen 1857: 137) Müller Argoviensis (1866: 662)

- Petiolar glands cupuliform or patelliform, sessile; inflorescences without a distinct sterile zone between pistillate and staminate flowers; styles 4-fid to multifid ...................................................................................................................................................... 10

10. Leaf blades elliptic or oblong, base acute or asymmetric; pistillate sepals oblong or lanceolate, margins entire ( Fig. 5A, B ) .......... ............................................................................................................................... C. odontadenius Müller Argoviensis (1873: 227)

- Leaf blades usually ovate, base obtuse; pistillate sepals obovate to oblanceolate, margins serrate ( Fig. 5H ) .................................... ............................................................................................ C. sclerocalyx ( Didrichsen 1857: 134) Müller Argoviensis (1865: 134)

11. Subshrubs without xylopodium, leaf margins without glands in the sinuses; bracts with pyriform glands .................................. 12

- Subshrubs with xylopodium, leaf margins with glands in the sinuses; bracts without glands ....................................................... 13

12. Petioles with cylindric-clavate glands; leaf blades covered with hispid trichomes on the adaxial surface; bracts with stipitate glands ( Fig. 4G, H ) .................................................................................................................... C. hirtus L’Héritier de Brutelle (1784: 17)

- Petioles with cupuliform glands; leaf blades covered with stellate-porrect trichomes on the adaxial surface; bracts with sessile glands ( Fig. 6I, J ) .................................................................................................................. C. glandulosus Linnaeus (1759: 1275)

13. Leaf blades with pinnate venation, but with palmate veins basally, one pair of lower secondary veins surpassing half the length of the blade .......................................................................................................................................................................................... 14

- Leaf blades with only pinnate venation, the lower secondary veins never exceeding half the length of the blade ....................... 15

14. Petioles with 4–8 apical glands; pistillate sepals lanceolate; staminate petals glabrous externally; filaments glabrous ( Fig. 5F, G ). ................................................................................................................................. C. pycnadenius Müller Argoviensis (1873: 216)

- Petioles with 2 apical glands; pistillate sepals ovate, suborbicular or obovate; staminate petals villous on both surfaces; filaments villous ( Fig. 6A, B ) ........................................................................................................................................................ C. abaitensis

15. Pistillate sepals externally stellate, internally glabrous; styles glabrous or glabrescent; petals internally villous, externally glabrous ........................................................................................................................................................................................... 16

- Pistillate sepals stellate on both surfaces; styles stellate; petals villous on both surfaces .............................................................. 18

16. Stems yellowish to ferrugineous, abaxial surface of leaf blades densely covered with stellate-porrect trichomes, tomentose to the touch ( Fig. 6G, H ) ....................................................................................................................................................... C. desertorum

- Stems greenish to brownish, abaxial surface of leaf blades sparsely covered with stiffly stellate trichomes................................. 17

17. Leaf blades linear to narrowly elliptic; ovary shortly tomentose, covered with stellate trichomes without a porrect central ray; styles 2-fid ( Fig. 4A–C ) ......................................................................................... C. gracilescens Müller Argoviensis (1865: 110)

- Leaf blades oblong to elliptic; ovary hispid, covered with stellate trichomes with a porrect central ray; styles 4(–2)-fid ( Fig. 6F ). ................................................................................................................................................................................ C. antisyphiliticus

18. Stems canescent to pinkish; petioles with orange to reddish glands; leaf blades usually ovate ( Fig. 4I–K ) ...................................... ................................................................................................................................................ C. inaequilobus Steyermark (1958: 7)

- Stems greenish, brownish, or yellowish; petioles with or without yellowish glands; leaf blades elliptic, oblong, or lanceolate .. 19

19. Much-branched shrubs to 2 m tall; pistillate sepals equal or subequal, usually ovate or ovate-lanceolate; capsules oblongoid, fruiting calyces not exceeding half of the capsule length; seeds oblongoid, without spots ( Fig. 2 ) ....................... C. ramosissimus

- Few-branched subshrubs less than 1 m tall; pistillate sepals unequal, obovate, oblong, or ovate; capsules globoid, fruiting calyces about as long as the capsule; seeds ovoid, with spots .................................................................................................................... 20

20. Petioles usually without glands; leaf blades with acute or obtuse base; staminate bracts 1.1–2.7 mm long; filaments villous ( Fig. 5C ) ................................................................................................... C. planaltoanus M. J. Silva & Sodré in Silva et al. (2014: 89)

- Petioles usually with glands; leaf blades with slightly cordate base; staminate bracts 4–6.5 mm long; filaments glabrous ......... 21

21. Petioles with stipitate-patelliform glands; pistillate sepals entire; staminate petals obovate-oblanceolate ( Fig. 5K–M ) ................... ...................................................................................................................................................................................... C. tamberlikii

- Petioles with sessile disciform glands; pistillate sepals serrate; staminate petals lanceolate to oblong ( Fig. 5I, J ) .............. C. spica

Figures

FIGURE 2. Croton ramosissimus. A. Habit. B. Inflorescence showing pistillate and staminate flowers. C and D. Inflorescences showing pistillate flowers and staminate buds. E. Fruits. Photographs by the authors.

FIGURE 4.Diversity of Crotonsection Geiseleriainthe stateof GoiásandFederal District.A–C. C.gracilescens.A.Habit.B.Inflorescence showing pistillate flowers and staminate buds. C. Fruits. D–F. C. gracilirameus. D. Habit. E. Inflorescence showing staminate flowers and buds. F. Pistillate flower. G and H. C. hirtus. G. Flowering branch. H. Inflorescence showing pistillate flowers, staminate flowers and buds. I–K. C. inaequilobus. I. Flowering branches. J. Inflorescence showing pistillate flowers, staminate flowers and buds. K. Fertile branch showing fruits on the left and leaf with reddish petiolar glands on the right. L and M. C. junceus. L. Habit. M. Fruit and petiolar gland (right). N and O. C. lundianus. N. Habit. O. Inflorescence showing pistillate flowers at the base and staminate buds on the apical portion of the axis.

FIGURE 5. Diversity of Croton section Geiseleria in the state of Goiás and Federal District. A and B. C. odontadenius. A. Habit. B. Staminate flowers and buds. C. C. planaltoanus. Habit. D and E. C. pulegiodorus. D. Flowering branch. E. Inflorescence showing pistillate flowers and staminate flowers and buds. F and G. C. pycnadenius. F. Habit. G. Inflorescence showing pistillate flowers and fruits. H. C. sclerocalyx. Fertile branch. I and J. C. spica. I. Habit. J. Inflorescence showing pistillate flowers and staminate buds. K–M. C. tamberlikii. K. Habit. L. Inflorescence showing staminate flowers and buds. M. Inflorescence showing pistillate flowers.

FIGURE 6. Diversity of Croton section Geiseleria in the state of Goiás and Federal District. A and B. C. abaitensis. A. Habit. B. Detail of inflorescence showing young fruits. C–E. C. agoensis. C. Flowering branch. D. Inflorescence showing pistillate flowers. E. Inflorescence showing staminate flowers and buds. F. C. antisyphiliticus. Fruiting branch. G and H. C. desertorum. G. Habit. H. Flowering branch. I and J. C. glandulosus. I. Flowering branch. J. Fruits. K and L. C. goyazensis. K. Flowering branch. L. Inflorescence showing staminate flowers and buds.